1. Field of the Invention
This invention relates to an inertia sensor unit mounted on vehicles and the like.
Priority is claimed on Japanese Patent Application No. 2003-359097, filed Oct. 20, 2003, the content of which is incorporated herein by reference.
2. Description of Related Art
Conventionally, in observing a position or an orientation of vehicles, a flying object and the like, measurement of angular velocity and acceleration is performed and, for this reason, inertia sensors, such as an angular velocity sensor and an acceleration sensor, are used. It is general to convert the analog electricity signals output from inertia sensors, such as an angular velocity sensor and an acceleration sensor into digital signals corresponding to resolutions as occasion demands, respectively, through an A/D converter.
Moreover, it is also common to correct signals output from an angular velocity sensor and an acceleration sensor with the circumferential temperature around the angular velocity sensor and the acceleration sensor detected by the temperature sensor provided in an ASIC which processes the output signal of a sensor or a sensor unit, because the output of the angular velocity sensor or the acceleration sensor has a temperature dependency. For example, such a sensor is disclosed in the Japanese Patent Application Laid-Open Nos. H09-311140 and 2000-111348.
However, the above traditional sensors have a problem that the signals output from the angular sensor and the acceleration sensor cannot be accurately corrected with the temperature detected by the temperature sensor, because the temperature detected by the temperature sensor may differ depending on the number and arrangement of the temperature sensor, i.e. in the case in which the temperature is elevated by the heat generated by the ASIC and the microcomputer itself which processes the output signal of a sensor, and the case in which the temperature is elevated by the heat from an outer environment, although the accuracy of the output from the sensor is improved compared with the case of doing nothing.
In particular, in an inertia sensor in which a detecting element and a signal-processor for processing the signals output from the detecting element are constituted as individual elements respectively, there was a problem that each output signals could not be corrected accurately with the exact temperature depending on the arrangement place of the temperature sensor, because a difference in temperature occurred between the detecting element and the signal-processor.